Secreção de prostaglandinas antes, durante e após a luteólise em bovinos

Detalhes bibliográficos
Autor(a) principal: Pugliesi, Guilherme
Data de Publicação: 2012
Tipo de documento: Tese
Idioma: por
Título da fonte: LOCUS Repositório Institucional da UFV
Texto Completo: http://locus.ufv.br/handle/123456789/1800
Resumo: The current study was done with the aim to evaluate the role of prostaglandin F2&#945; (PGF2&#945;) synthesis before, during, and afer the luteolytic period on functional and morphological corpus luteum (CL) regression; study the effects of estradiol-17&#946; (E2) in diferrent physiological levels on PGF2&#945; secretion and induction of luteolysis; and evaluate the effects of prostaglandin inhibition during postluteolysis on follicular growth and ovulation in heifers. Four sequential studies were done. The first (Study 1) was elaborated from two experiments, and the other three studies (Studies 2, 3 and 4) were compound by one experiment each. The Study 1 aimed to evaluate the inhibition of the synthesis of prostaglandin F2&#945; (PGF2&#945;) during preluteolytic and luteolytic periods, based on plasma concentrations of a PGF2&#945; metabolite (PGFM). In Experiment 1, flunixin meglumine (FM; 2.5 mg/kg) was given to heifers (n = 4/group) in diferrent doses (0, 0.5, 1.0, or 1.5 g) 16 days after ovulation to evaluate the minimal effective dose during the expected luteolytic period. The dose of 1.5 g (equivalent to 2.5 mg/kg bw) was the most effective. Therefore, in Experiment 2 FM (2.5 mg/kg) was given to heifers at three 8-h intervals, 16 days after ovulation (first treatment = Hour 0). Blood samples were collected at 8-h intervals from 15 to 18 d postovulation in a vehicle (control) and FM group (n = 16/group). Hourly samples were collected from Hours &#8722;2 to 28 in 10 heifers in each group. Heifers that were in preluteolysis or luteolysis at Hour 0 based on plasma progesterone (P4) concentrations at 8-h intervals were partitioned into preluteolytic and luteolytic subgroups. Concentration of PGFM was reduced (P < 0.05) by FM treatment in each subgroup. For the preluteolytic subgroup, the first decrease (P < 0.05) in P4 concentration after Hour 0 occurred at Hours 24 and 40 in the vehicle and FM groups, respectively. Plasma P4 concentrations 32 and 40 h after the beginning of luteolysis in the luteolytic subgroup were greater (P < 0.05) in the FM group. Concentration at the peak of a PGFM pulse in the FM group was greater (P < 0.05) in the luteolytic than in the preluteolytic subgroup. In the second study (Study 2), we aimed to evaluate the effect of E2 concentration on the prominence of PGFM pulses and the relationship between prominence and intrapulse concentration of P4, luinizing hormone (LH), and luteal blood flow were studied. A single dose of 0 (vehicle), 0.01, 0.05, or 0.1 mg of E2 was given (n=6/group) 14 days after ovulation. Blood samples were collected and luteal blood flow was evaluated hourly for 10 h after the treatment. The 0.05-mg dose increased and the 0.1 mg further increased the prominence of the induced PGFM pulse, compared to the 0.0-mg dose and the 0.01-mg dose. The PGFM pulses were subdivided into three different prominence categories (< 50, 50&#8722;150, and > 150 pg/mL at the peak). In the 50 150 category, P4 concentration increased (P < 0.05) between &#8722;2 h and 0 h (0 h = peak of PGFM pulse). In the >150 category, P4 decreased (P < 0.05) between &#8722;1 h and 0 h, LH increased (P < 0.05) at 1 h, and luteal blood flow apparently decreased (P < 0.05) at 2 h of the PGFM pulse. The novel results supported the following hypotheses: 1) an increase in E2 concentration increases the prominence of a PGFM pulse, and 2) greater prominence of a PGFM pulse is associated with a greater transient intrapulse depression of P4 at the peak of the PGFM pulse. In addition, the extent of the effect of PGF2&#945; on the increase in LH and changes in blood flow within the hours of a PGFM pulse was related positively to the prominence of the PGFM pulse. In the subsequent study (Study 3), we aimed to elucidate the effects of sequential induction of PGFM pulses by E2 on prominence of PGFM pulses and P4 concentration. Three treatments of vehicle (n = 12) or E2 (n = 12) at doses of 0.05 mg or 0.1 mg were given at 12-h intervals beginning on day 15 postovulation. Blood samples were collected every 12 h from days 13 to 24 postovulation and hourly for 12 h after the first and third treatments. On day 15, all heifers were in preluteolysis and on day 16 were in preluteolysis in the vehicle-treated heifers (n = 11) and either preluteolysis (n = 4) or luteolysis (n = 8) in the E2-treated heifers. Peak concentration of induced PGFM pulses during preluteolysis on day 15 was greater (P < 0.04) than for pulses during preluteolysis on day 16. The interval from ovulation to the beginning of luteolysis was shorter (P < 0.04) in the E2-treated heifers than in the vehicle-treated heifers. An E2-induced PGFM pulse was less prominent (P < 0.008) in heifers in temporal association with a transient resurgence in P4 than in heifers with a progressive P4 decrease. The hypothesis that repeated E2 exposure stimulates increasing prominence of PGFM pulses was not supported. Instead, repeated exposure reduced the prominence of PGFM pulses in contrast to the stimulation from the first E2 treatment. Results indicated for the first time that reduced prominence of a PGF2&#945; pulse during luteolysis can lead to a transient resurgence in P4 concentration. The Study 4 aimed to study the effects of prostaglandin inhibition during postluteolysis on CL regression, prolactin (PRL) secretion, and follicle growth and ovulation in heifers. The beginning of postluteolysis (P4 < 1 ng/mL) was targeted by using 8 h after ultrasonic detection of a 25% decrease in CL area (cm2) and was designated Hour 0. FM (2.5 mg/kg; n = 10) to inhibit PGF2&#945; secretion or vehicle (n = 9) were given intramuscularly at Hours 0, 4, 8, 16, 24, 32, and 40. Blood sampling and measurement of the CL and dominant follicle were done every 8 h beginning 14 days postovulation in each group. Blood samples for detection of pulses of PRL and pulses of PGFM were obtained every hour for 24 h beginning at Hour 0. Pulse concentrations of both PGFM and PRL were lower in the FM group than in the vehicle group. Concentration of PRL was greatest at the peak of a PGFM pulse. Neither CL area (cm2) nor P4 concentration differed between groups during Hours 0 to 48 (postluteolysis). Ovulation occurred in nine of nine heifers in the vehicle group and in three of 10 heifers in the FM group. The anovulatory follicles in the FM group grew to 36.2 ± 2.9 mm, and the wall became thickened from apparent luteinization. The hypothesis that PGF2&#945; was involved in the continued P4 decrease and structural CL regression during postluteolysis was not supported. The hypotheses that pulses of PGFM and PRL were temporally related and that systemic FM treatment induced an anovulatory follicle were supported.
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spelling Pugliesi, Guilhermehttp://lattes.cnpq.br/1823619955314799Torres, Ciro Alexandre Alveshttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4787213D4Ginther, Oliver JosephCarvalho, Giovanni Ribeiro dehttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4723068Z6Borges, Alan Maiahttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4796232T6Costa, Eduardo Paulino dahttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4787237D6Guimarães, José Domingoshttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4782270U62015-03-26T12:54:42Z2013-05-022015-03-26T12:54:42Z2012-05-16PUGLIESI, Guilherme. Role of prostaglandins secretion before, during, and after luteolysis in cattle. 2012. 180 f. Tese (Doutorado em Genética e Melhoramento de Animais Domésticos; Nutrição e Alimentação Animal; Pastagens e Forragicul) - Universidade Federal de Viçosa, Viçosa, 2012.http://locus.ufv.br/handle/123456789/1800The current study was done with the aim to evaluate the role of prostaglandin F2&#945; (PGF2&#945;) synthesis before, during, and afer the luteolytic period on functional and morphological corpus luteum (CL) regression; study the effects of estradiol-17&#946; (E2) in diferrent physiological levels on PGF2&#945; secretion and induction of luteolysis; and evaluate the effects of prostaglandin inhibition during postluteolysis on follicular growth and ovulation in heifers. Four sequential studies were done. The first (Study 1) was elaborated from two experiments, and the other three studies (Studies 2, 3 and 4) were compound by one experiment each. The Study 1 aimed to evaluate the inhibition of the synthesis of prostaglandin F2&#945; (PGF2&#945;) during preluteolytic and luteolytic periods, based on plasma concentrations of a PGF2&#945; metabolite (PGFM). In Experiment 1, flunixin meglumine (FM; 2.5 mg/kg) was given to heifers (n = 4/group) in diferrent doses (0, 0.5, 1.0, or 1.5 g) 16 days after ovulation to evaluate the minimal effective dose during the expected luteolytic period. The dose of 1.5 g (equivalent to 2.5 mg/kg bw) was the most effective. Therefore, in Experiment 2 FM (2.5 mg/kg) was given to heifers at three 8-h intervals, 16 days after ovulation (first treatment = Hour 0). Blood samples were collected at 8-h intervals from 15 to 18 d postovulation in a vehicle (control) and FM group (n = 16/group). Hourly samples were collected from Hours &#8722;2 to 28 in 10 heifers in each group. Heifers that were in preluteolysis or luteolysis at Hour 0 based on plasma progesterone (P4) concentrations at 8-h intervals were partitioned into preluteolytic and luteolytic subgroups. Concentration of PGFM was reduced (P < 0.05) by FM treatment in each subgroup. For the preluteolytic subgroup, the first decrease (P < 0.05) in P4 concentration after Hour 0 occurred at Hours 24 and 40 in the vehicle and FM groups, respectively. Plasma P4 concentrations 32 and 40 h after the beginning of luteolysis in the luteolytic subgroup were greater (P < 0.05) in the FM group. Concentration at the peak of a PGFM pulse in the FM group was greater (P < 0.05) in the luteolytic than in the preluteolytic subgroup. In the second study (Study 2), we aimed to evaluate the effect of E2 concentration on the prominence of PGFM pulses and the relationship between prominence and intrapulse concentration of P4, luinizing hormone (LH), and luteal blood flow were studied. A single dose of 0 (vehicle), 0.01, 0.05, or 0.1 mg of E2 was given (n=6/group) 14 days after ovulation. Blood samples were collected and luteal blood flow was evaluated hourly for 10 h after the treatment. The 0.05-mg dose increased and the 0.1 mg further increased the prominence of the induced PGFM pulse, compared to the 0.0-mg dose and the 0.01-mg dose. The PGFM pulses were subdivided into three different prominence categories (< 50, 50&#8722;150, and > 150 pg/mL at the peak). In the 50 150 category, P4 concentration increased (P < 0.05) between &#8722;2 h and 0 h (0 h = peak of PGFM pulse). In the >150 category, P4 decreased (P < 0.05) between &#8722;1 h and 0 h, LH increased (P < 0.05) at 1 h, and luteal blood flow apparently decreased (P < 0.05) at 2 h of the PGFM pulse. The novel results supported the following hypotheses: 1) an increase in E2 concentration increases the prominence of a PGFM pulse, and 2) greater prominence of a PGFM pulse is associated with a greater transient intrapulse depression of P4 at the peak of the PGFM pulse. In addition, the extent of the effect of PGF2&#945; on the increase in LH and changes in blood flow within the hours of a PGFM pulse was related positively to the prominence of the PGFM pulse. In the subsequent study (Study 3), we aimed to elucidate the effects of sequential induction of PGFM pulses by E2 on prominence of PGFM pulses and P4 concentration. Three treatments of vehicle (n = 12) or E2 (n = 12) at doses of 0.05 mg or 0.1 mg were given at 12-h intervals beginning on day 15 postovulation. Blood samples were collected every 12 h from days 13 to 24 postovulation and hourly for 12 h after the first and third treatments. On day 15, all heifers were in preluteolysis and on day 16 were in preluteolysis in the vehicle-treated heifers (n = 11) and either preluteolysis (n = 4) or luteolysis (n = 8) in the E2-treated heifers. Peak concentration of induced PGFM pulses during preluteolysis on day 15 was greater (P < 0.04) than for pulses during preluteolysis on day 16. The interval from ovulation to the beginning of luteolysis was shorter (P < 0.04) in the E2-treated heifers than in the vehicle-treated heifers. An E2-induced PGFM pulse was less prominent (P < 0.008) in heifers in temporal association with a transient resurgence in P4 than in heifers with a progressive P4 decrease. The hypothesis that repeated E2 exposure stimulates increasing prominence of PGFM pulses was not supported. Instead, repeated exposure reduced the prominence of PGFM pulses in contrast to the stimulation from the first E2 treatment. Results indicated for the first time that reduced prominence of a PGF2&#945; pulse during luteolysis can lead to a transient resurgence in P4 concentration. The Study 4 aimed to study the effects of prostaglandin inhibition during postluteolysis on CL regression, prolactin (PRL) secretion, and follicle growth and ovulation in heifers. The beginning of postluteolysis (P4 < 1 ng/mL) was targeted by using 8 h after ultrasonic detection of a 25% decrease in CL area (cm2) and was designated Hour 0. FM (2.5 mg/kg; n = 10) to inhibit PGF2&#945; secretion or vehicle (n = 9) were given intramuscularly at Hours 0, 4, 8, 16, 24, 32, and 40. Blood sampling and measurement of the CL and dominant follicle were done every 8 h beginning 14 days postovulation in each group. Blood samples for detection of pulses of PRL and pulses of PGFM were obtained every hour for 24 h beginning at Hour 0. Pulse concentrations of both PGFM and PRL were lower in the FM group than in the vehicle group. Concentration of PRL was greatest at the peak of a PGFM pulse. Neither CL area (cm2) nor P4 concentration differed between groups during Hours 0 to 48 (postluteolysis). Ovulation occurred in nine of nine heifers in the vehicle group and in three of 10 heifers in the FM group. The anovulatory follicles in the FM group grew to 36.2 ± 2.9 mm, and the wall became thickened from apparent luteinization. The hypothesis that PGF2&#945; was involved in the continued P4 decrease and structural CL regression during postluteolysis was not supported. The hypotheses that pulses of PGFM and PRL were temporally related and that systemic FM treatment induced an anovulatory follicle were supported.O presente estudo foi elaborado com o objetivo de avaliar o papel da secreção de prostaglandina F2&#945; (PGF2&#945;) antes, durante e após o período luteolítico na regressão funcional e estrutural do corpo lúteo (CL) em novilhas; elucidar os efeitos do estradiol-17&#946; (E2) em diferentes níveis fisiológicos na secreção de PGF2&#945; e indução da luteólise; e estudar os efeitos da inibição das prostagladinas no período pós-luteolítico sobre o crescimento folicular e ovulação. Foram realizados quatro estudos sequenciais, sendo o primeiro estudo (Estudo 1) composto por dois experimentos e os demais estudos (Estudos 2, 3 e 4) compostos por um experimento cada. No Estudo 1 objetivou-se avaliar os efeitos da inibição da síntese de PGF2&#945; durante os períodos de pré-luteólise e luteólise, baseando-se na mensuração da concentração plasmática do metabólito da PGF2&#945; (PGFM). Para isto, no Experimento 1, flunexine meglumine (FM) foi administrado em diferentes doses (0, 0,5, 1,0 ou 1,5 g) em novilhas (n = 4/grupo) no 16º dia pós-ovulação para se determinar a dose mínima eficaz para inibir a síntese de PGF2&#945; no período esperado da luteólise espontânea. A dose de 1,5 g, que correspondeu em média 2,5 mg/kg de peso vivo, foi mais eficaz em reduzir as concentrações de PGFM comparada as demais doses. Assim, no Experimento 2, FM (2,5 mg/kg) foi administrado a cada 8 horas por 24 horas (primeiro tratamento = Hora 0 no 15º dia pós-ovulação). Amostras de sangue foram colhidas em intervalos de 8 horas do 15º ao 18º dia pós-ovulação em um grupo veículo (controle) e um grupo tratado com FM (n = 16/grupo). Adicionalmente, amostras de sangue foram colhidas de hora em hora da Hora &#8722;2 a 28 em 10 novilhas de cada grupo. As novilhas foram subdivididas naquelas que estavam em pré-luteólise e luteólise na Hora 0 baseado nas concentrações plasmáticas de progesterona (P4) realizadas de 8 em 8 horas. As concentrações de PGFM foram reduzidas (P < 0,05) pelo tratamento com FM em cada subgrupo. Para o subgrupo pré-luteolítico, o primeiro decréscimo (P < 0,05) nas concentrações de P4 ocorreu, respectivamente, nas Horas 24 e 40 nos grupos veículo e FM. As concentrações de P4, 32 e 40 horas após o início da luteólise no subgrupo luteolítico foram maiores (P < 0,05) no grupo FM. As concentrações de PGFM no pico do pulso de PGFM no grupo FM foram maiores (P < 0,05) no subgrupo luteolítico do que no subgrupo pré-luteolítico. No segundo estudo (Estudo 2), objetivou-se estudar o efeito da concentração de E2 na proeminência dos pulsos de PGFM e sua relação com as concentrações de P4, hormônio luteinizante (LH), e fluxo sanguíneo luteal em novilhas em pré-luteólise. Para isto, uma única dose de 0 (veículo), 0,01, 0,05, ou 0,1 mg de E2 foi administrado (n=6/grupo) 14 dias pós-ovulação. Amostras de sangue foram colhidas e o fluxo sanguíneo luteal estimado de hora em hora por 10 horas logo após o tratamento. A dose de 0,05 mg resultou em um aumento intermediário e a dose de 0,1-mg promoveu um aumento mais pronunciado no pulso de PGFM, comparado com as doses de 0,0 e 0,01 mg. Todos os pulsos de PGFM foram agrupados e subdivididos em três diferentes categorias de proeminência (< 50, 50&#8722;150, e > 150 pg/mL no pico do pulso). Na categoria de 50 150, a concentração de P4 aumentou (P < 0,05) no pico do pulso de PGFM. Na categoria >150, a concentração de P4 reduziu (P < 0,05) no pico dos pulsos de PGFM, a de LH aumentou (P < 0,05) após uma hora do pico, e o fluxo sanguíneo luteal aparentemente reduziu (P < 0,05) 2 h após o pico de PGFM. Os resultados suportaram as seguintes hipóteses: 1) um aumento nas concentrações de E2 eleva a proeminência do pulso de PGFM, e 2) a maior proeminência do pulso de PGFM é associado com maior depressão de P4 no pico do pulso de PGFM. Adicionalmente, a dimensão do efeito da PGF2&#945; no aumento das concentrações de LH e nas mudanças do fluxo sanguíneo luteal dentro das horas de um pulso de PGFM foi positivamente relacionada com a proeminência do pulso de PGFM. No estudo subsequente (Estudo 3), objetivou-se elucidar os efeitos da indução sequencial de pulsos de PGFM pelo tratamento com E2 sobre a proeminência dos pulsos de PGFM e na indução da luteólise. Três tratamentos com veículo (n = 12) ou E2 (n = 12) nas doses de 0,05 mg ou 0,1 mg foram administrados em intervalos de 12 horas, iniciando-se no 15º dia pós-ovulação. Amostras de sangue foram colhidas a cada 12 horas entre o 13º e o 24º dia pós-ovulação, e de hora em hora por um período de 12 horas após o primeiro e o terceiro tratamentos. No dia 15 pós-ovulação, todas as novilhas estavam em fase de pré-luteólise e no dia 16 estavam em préluteólise no grupo administrado veículo (n =11) e em pré-luteólise (n = 4) ou luteólise (n = 8) no grupo tratado com E2. A concentração de PGFM no pico dos pulsos de PGFM induzidos durante o período de pré-luteólise no 15º dia pós-ovulação foi maior (P < 0,04) do que dos pulsos de PGFM pré-luteolíticos no 16º dia pós-ovulação. O intervalo da ovulação até o início da luteólise foi reduzido (P < 0,05) nas novilhas tratadas com E2 quando comparado as demais novilhas não tratadas (veículo). O pulso de PGFM induzido pelo E2 foi menos proeminente (P < 0,008) nas novilhas que apresentaram resurgência transitória das concentrações de P4 do que nas novilhas que apresentaram um decréscimo progressivo da P4. A hipótese que a exposição repetida ao E2 estimula o aumento da proeminência dos pulsos de PGFM não foi suportada. Ao contrário, a exposição repetida reduziu a proeminência dos pulsos de PGFM em contraste ao estímullo promovido após o primeiro tratamento. Estes resultados indicaram pela primeira vez que a redução na proeminência dos pulsos de PGF2&#945; durante a luteólise pode resultar em resurgimento transitório na concentração de P4. No Estudo 4, objetivou-se avaliar os efeitos da inibição da síntese de prostaglandinas durante a pós-luteólise na regressão do CL, secreção de prolactina (PRL), e crescimento folicular e ovulação em novilhas. O início da pós-luteólise (P4 < 1 ng/mL) foi identificado e definido como 8 horas após a detecção pela ultrassonografia de 25% de redução na área (cm2) do CL, e foi assim designado Hora 0. Foi administrado via intramuscular FM (2,5 mg/kg; n = 10) para inibir a secreção de PGF2&#945; ou veículo (n = 9) nas Horas 0, 4, 8, 16, 24, 32, e 40. Foi realizado amostragem sanguínea e mensuração do CL e do folículo dominante a cada 8 horas iniciando no 14º dia pós-ovulação. Amostras de sangue foram também colhidas de hora em hora por 24 horas iniciando na Hora 0 para detecção dos pulsos de PRL e PGFM. As concentrações nos pulsos de PGFM e PRL foram inferiores no grupo FM comparado ao grupo veículo. A concentração de PRL foi maior no pico do pulso de PGFM do que nas demais horas do pulso. Tanto a área do CL quanto a concentração de P4 não diferiram entre os grupos durante as Horas 0 a 48 (pós-luteólise). A ovulação ocorreu em nove de nove novilhas no grupo veículo e em três de 10 novilhas do grupo FM. Os folículos anovulatórios no grupo FM cresceram até 36,2 ± 2,9 mm, e a parede folicular se apresentou espessada em decorrência de aparente luteinização. A hipótese que a PGF2&#945; estava envolvida na redução continua da secreção de P4 e na regressão estrutural do CL durante a pós-luteólise não foi suportada. As hipóteses que os pulsos de PGFM e PRL estavam temporariamente relacionados e que o tratamento com FM sistêmico induziu a formação de folículos anovulatórios foram suportadas.Coordenação de Aperfeiçoamento de Pessoal de Nível Superiorapplication/pdfporUniversidade Federal de ViçosaDoutorado em ZootecniaUFVBRGenética e Melhoramento de Animais Domésticos; Nutrição e Alimentação Animal; Pastagens e ForragiculProgesteronaCiclo estralProgesteroneEstrous cycleCNPQ::CIENCIAS AGRARIAS::MEDICINA VETERINARIA::REPRODUCAO ANIMALSecreção de prostaglandinas antes, durante e após a luteólise em bovinosSecreção de prostaglandinas antes, durante e após a luteólise em bovinosRole of prostaglandins secretion before, during, and after luteolysis in cattleRole of prostaglandins secretion before, during, and after luteolysis in cattleinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/doctoralThesisinfo:eu-repo/semantics/openAccessreponame:LOCUS Repositório Institucional da UFVinstname:Universidade Federal de Viçosa (UFV)instacron:UFVORIGINALtexto completo.pdfapplication/pdf1733058https://locus.ufv.br//bitstream/123456789/1800/1/texto%20completo.pdf1504d6c99d9d0b52f7505e9ea2975761MD51TEXTtexto completo.pdf.txttexto completo.pdf.txtExtracted texttext/plain373261https://locus.ufv.br//bitstream/123456789/1800/2/texto%20completo.pdf.txtb1779f54b34c8e495e4e2b4ce46f070dMD52THUMBNAILtexto completo.pdf.jpgtexto completo.pdf.jpgIM Thumbnailimage/jpeg3435https://locus.ufv.br//bitstream/123456789/1800/3/texto%20completo.pdf.jpg6a20e28c774b369ea1bcae1e78b42893MD53123456789/18002016-04-07 23:13:18.945oai:locus.ufv.br:123456789/1800Repositório InstitucionalPUBhttps://www.locus.ufv.br/oai/requestfabiojreis@ufv.bropendoar:21452016-04-08T02:13:18LOCUS Repositório Institucional da UFV - Universidade Federal de Viçosa (UFV)false
dc.title.por.fl_str_mv Secreção de prostaglandinas antes, durante e após a luteólise em bovinos
Secreção de prostaglandinas antes, durante e após a luteólise em bovinos
dc.title.alternative.eng.fl_str_mv Role of prostaglandins secretion before, during, and after luteolysis in cattle
Role of prostaglandins secretion before, during, and after luteolysis in cattle
title Secreção de prostaglandinas antes, durante e após a luteólise em bovinos
spellingShingle Secreção de prostaglandinas antes, durante e após a luteólise em bovinos
Pugliesi, Guilherme
Progesterona
Ciclo estral
Progesterone
Estrous cycle
CNPQ::CIENCIAS AGRARIAS::MEDICINA VETERINARIA::REPRODUCAO ANIMAL
title_short Secreção de prostaglandinas antes, durante e após a luteólise em bovinos
title_full Secreção de prostaglandinas antes, durante e após a luteólise em bovinos
title_fullStr Secreção de prostaglandinas antes, durante e após a luteólise em bovinos
title_full_unstemmed Secreção de prostaglandinas antes, durante e após a luteólise em bovinos
title_sort Secreção de prostaglandinas antes, durante e após a luteólise em bovinos
author Pugliesi, Guilherme
author_facet Pugliesi, Guilherme
author_role author
dc.contributor.authorLattes.por.fl_str_mv http://lattes.cnpq.br/1823619955314799
dc.contributor.author.fl_str_mv Pugliesi, Guilherme
dc.contributor.advisor-co1.fl_str_mv Torres, Ciro Alexandre Alves
dc.contributor.advisor-co1Lattes.fl_str_mv http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4787213D4
dc.contributor.advisor-co2.fl_str_mv Ginther, Oliver Joseph
dc.contributor.advisor1.fl_str_mv Carvalho, Giovanni Ribeiro de
dc.contributor.advisor1Lattes.fl_str_mv http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4723068Z6
dc.contributor.referee1.fl_str_mv Borges, Alan Maia
dc.contributor.referee1Lattes.fl_str_mv http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4796232T6
dc.contributor.referee2.fl_str_mv Costa, Eduardo Paulino da
dc.contributor.referee2Lattes.fl_str_mv http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4787237D6
dc.contributor.referee3.fl_str_mv Guimarães, José Domingos
dc.contributor.referee3Lattes.fl_str_mv http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4782270U6
contributor_str_mv Torres, Ciro Alexandre Alves
Ginther, Oliver Joseph
Carvalho, Giovanni Ribeiro de
Borges, Alan Maia
Costa, Eduardo Paulino da
Guimarães, José Domingos
dc.subject.por.fl_str_mv Progesterona
Ciclo estral
topic Progesterona
Ciclo estral
Progesterone
Estrous cycle
CNPQ::CIENCIAS AGRARIAS::MEDICINA VETERINARIA::REPRODUCAO ANIMAL
dc.subject.eng.fl_str_mv Progesterone
Estrous cycle
dc.subject.cnpq.fl_str_mv CNPQ::CIENCIAS AGRARIAS::MEDICINA VETERINARIA::REPRODUCAO ANIMAL
description The current study was done with the aim to evaluate the role of prostaglandin F2&#945; (PGF2&#945;) synthesis before, during, and afer the luteolytic period on functional and morphological corpus luteum (CL) regression; study the effects of estradiol-17&#946; (E2) in diferrent physiological levels on PGF2&#945; secretion and induction of luteolysis; and evaluate the effects of prostaglandin inhibition during postluteolysis on follicular growth and ovulation in heifers. Four sequential studies were done. The first (Study 1) was elaborated from two experiments, and the other three studies (Studies 2, 3 and 4) were compound by one experiment each. The Study 1 aimed to evaluate the inhibition of the synthesis of prostaglandin F2&#945; (PGF2&#945;) during preluteolytic and luteolytic periods, based on plasma concentrations of a PGF2&#945; metabolite (PGFM). In Experiment 1, flunixin meglumine (FM; 2.5 mg/kg) was given to heifers (n = 4/group) in diferrent doses (0, 0.5, 1.0, or 1.5 g) 16 days after ovulation to evaluate the minimal effective dose during the expected luteolytic period. The dose of 1.5 g (equivalent to 2.5 mg/kg bw) was the most effective. Therefore, in Experiment 2 FM (2.5 mg/kg) was given to heifers at three 8-h intervals, 16 days after ovulation (first treatment = Hour 0). Blood samples were collected at 8-h intervals from 15 to 18 d postovulation in a vehicle (control) and FM group (n = 16/group). Hourly samples were collected from Hours &#8722;2 to 28 in 10 heifers in each group. Heifers that were in preluteolysis or luteolysis at Hour 0 based on plasma progesterone (P4) concentrations at 8-h intervals were partitioned into preluteolytic and luteolytic subgroups. Concentration of PGFM was reduced (P < 0.05) by FM treatment in each subgroup. For the preluteolytic subgroup, the first decrease (P < 0.05) in P4 concentration after Hour 0 occurred at Hours 24 and 40 in the vehicle and FM groups, respectively. Plasma P4 concentrations 32 and 40 h after the beginning of luteolysis in the luteolytic subgroup were greater (P < 0.05) in the FM group. Concentration at the peak of a PGFM pulse in the FM group was greater (P < 0.05) in the luteolytic than in the preluteolytic subgroup. In the second study (Study 2), we aimed to evaluate the effect of E2 concentration on the prominence of PGFM pulses and the relationship between prominence and intrapulse concentration of P4, luinizing hormone (LH), and luteal blood flow were studied. A single dose of 0 (vehicle), 0.01, 0.05, or 0.1 mg of E2 was given (n=6/group) 14 days after ovulation. Blood samples were collected and luteal blood flow was evaluated hourly for 10 h after the treatment. The 0.05-mg dose increased and the 0.1 mg further increased the prominence of the induced PGFM pulse, compared to the 0.0-mg dose and the 0.01-mg dose. The PGFM pulses were subdivided into three different prominence categories (< 50, 50&#8722;150, and > 150 pg/mL at the peak). In the 50 150 category, P4 concentration increased (P < 0.05) between &#8722;2 h and 0 h (0 h = peak of PGFM pulse). In the >150 category, P4 decreased (P < 0.05) between &#8722;1 h and 0 h, LH increased (P < 0.05) at 1 h, and luteal blood flow apparently decreased (P < 0.05) at 2 h of the PGFM pulse. The novel results supported the following hypotheses: 1) an increase in E2 concentration increases the prominence of a PGFM pulse, and 2) greater prominence of a PGFM pulse is associated with a greater transient intrapulse depression of P4 at the peak of the PGFM pulse. In addition, the extent of the effect of PGF2&#945; on the increase in LH and changes in blood flow within the hours of a PGFM pulse was related positively to the prominence of the PGFM pulse. In the subsequent study (Study 3), we aimed to elucidate the effects of sequential induction of PGFM pulses by E2 on prominence of PGFM pulses and P4 concentration. Three treatments of vehicle (n = 12) or E2 (n = 12) at doses of 0.05 mg or 0.1 mg were given at 12-h intervals beginning on day 15 postovulation. Blood samples were collected every 12 h from days 13 to 24 postovulation and hourly for 12 h after the first and third treatments. On day 15, all heifers were in preluteolysis and on day 16 were in preluteolysis in the vehicle-treated heifers (n = 11) and either preluteolysis (n = 4) or luteolysis (n = 8) in the E2-treated heifers. Peak concentration of induced PGFM pulses during preluteolysis on day 15 was greater (P < 0.04) than for pulses during preluteolysis on day 16. The interval from ovulation to the beginning of luteolysis was shorter (P < 0.04) in the E2-treated heifers than in the vehicle-treated heifers. An E2-induced PGFM pulse was less prominent (P < 0.008) in heifers in temporal association with a transient resurgence in P4 than in heifers with a progressive P4 decrease. The hypothesis that repeated E2 exposure stimulates increasing prominence of PGFM pulses was not supported. Instead, repeated exposure reduced the prominence of PGFM pulses in contrast to the stimulation from the first E2 treatment. Results indicated for the first time that reduced prominence of a PGF2&#945; pulse during luteolysis can lead to a transient resurgence in P4 concentration. The Study 4 aimed to study the effects of prostaglandin inhibition during postluteolysis on CL regression, prolactin (PRL) secretion, and follicle growth and ovulation in heifers. The beginning of postluteolysis (P4 < 1 ng/mL) was targeted by using 8 h after ultrasonic detection of a 25% decrease in CL area (cm2) and was designated Hour 0. FM (2.5 mg/kg; n = 10) to inhibit PGF2&#945; secretion or vehicle (n = 9) were given intramuscularly at Hours 0, 4, 8, 16, 24, 32, and 40. Blood sampling and measurement of the CL and dominant follicle were done every 8 h beginning 14 days postovulation in each group. Blood samples for detection of pulses of PRL and pulses of PGFM were obtained every hour for 24 h beginning at Hour 0. Pulse concentrations of both PGFM and PRL were lower in the FM group than in the vehicle group. Concentration of PRL was greatest at the peak of a PGFM pulse. Neither CL area (cm2) nor P4 concentration differed between groups during Hours 0 to 48 (postluteolysis). Ovulation occurred in nine of nine heifers in the vehicle group and in three of 10 heifers in the FM group. The anovulatory follicles in the FM group grew to 36.2 ± 2.9 mm, and the wall became thickened from apparent luteinization. The hypothesis that PGF2&#945; was involved in the continued P4 decrease and structural CL regression during postluteolysis was not supported. The hypotheses that pulses of PGFM and PRL were temporally related and that systemic FM treatment induced an anovulatory follicle were supported.
publishDate 2012
dc.date.issued.fl_str_mv 2012-05-16
dc.date.available.fl_str_mv 2013-05-02
2015-03-26T12:54:42Z
dc.date.accessioned.fl_str_mv 2015-03-26T12:54:42Z
dc.type.status.fl_str_mv info:eu-repo/semantics/publishedVersion
dc.type.driver.fl_str_mv info:eu-repo/semantics/doctoralThesis
format doctoralThesis
status_str publishedVersion
dc.identifier.citation.fl_str_mv PUGLIESI, Guilherme. Role of prostaglandins secretion before, during, and after luteolysis in cattle. 2012. 180 f. Tese (Doutorado em Genética e Melhoramento de Animais Domésticos; Nutrição e Alimentação Animal; Pastagens e Forragicul) - Universidade Federal de Viçosa, Viçosa, 2012.
dc.identifier.uri.fl_str_mv http://locus.ufv.br/handle/123456789/1800
identifier_str_mv PUGLIESI, Guilherme. Role of prostaglandins secretion before, during, and after luteolysis in cattle. 2012. 180 f. Tese (Doutorado em Genética e Melhoramento de Animais Domésticos; Nutrição e Alimentação Animal; Pastagens e Forragicul) - Universidade Federal de Viçosa, Viçosa, 2012.
url http://locus.ufv.br/handle/123456789/1800
dc.language.iso.fl_str_mv por
language por
dc.rights.driver.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
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dc.publisher.none.fl_str_mv Universidade Federal de Viçosa
dc.publisher.program.fl_str_mv Doutorado em Zootecnia
dc.publisher.initials.fl_str_mv UFV
dc.publisher.country.fl_str_mv BR
dc.publisher.department.fl_str_mv Genética e Melhoramento de Animais Domésticos; Nutrição e Alimentação Animal; Pastagens e Forragicul
publisher.none.fl_str_mv Universidade Federal de Viçosa
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instname:Universidade Federal de Viçosa (UFV)
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